NEW YORK (Reuters Health) - Mothers infected with hepatitis B virus (HBV) can safely breastfeed their babies, as long as they take a few important precautions, according to a new study.

It has been unclear whether breastfeeding would transmit HBV, researchers said in the Archives of Pediatrics & Adolescent Medicine, online May 2.

Their report, a review of past studies, allays those fears.

Even in mothers with the virus, "Breastfeeding should be recommended as a valuable source of nutrition to infants," study author Dr. Zhongjie Shi of Temple University in Philadelphia told Reuters Health in an email.

The researchers combined data from 10 previous studies, all conducted in China, which compared rates of hepatitis B in the babies of more than 1,000 mothers with the virus. About half of those mothers breastfed their babies.

All the babies were given proper immunoprophylaxis.

By their first birthday, 31 babies out of the 637 with breastfeeding mothers tested positive for hepatitis B. That compared to 33 babies out of 706 who had mothers who didn't breastfeed.

Most of those infants, the researchers explained, were infected with HBV either in utero or during birth.

The odds ratio of an infant developing hepatitis B surface antibodies in the breastfeeding group compared with the non-breastfeeding group was 0.98.

Mothers should avoid breastfeeding if they have cracked or bleeding nipples or lesions on their breasts, the authors note, as that facilitate transmission of the virus.

Dr. Shi concluded that while more studies on this topic are needed, the new results "are most valuable in developing countries and areas with high (hepatitis B) prevalence or heavy population, such as India, China, (and) south east Asia."